The Greenwich Time Ball is located at the prime meridian.
The prime meridian is a reference line through Greenwich, England that measures longitude east and west.
An example of prime meridian is zero degrees longitude.
the meridian from which longitude is measured both east and west; 0° longitude: it passes through Greenwich, England
- A meridian used as a reference line from which longitude east and west is measured.
- Prime Meridian The meridian passing through Greenwich, England, designated as the zero meridian (0°) by an international conference in 1884.
The meridian with a longitude of 0°, adopted officially in 1884 as a reference line from which longitude east and west are measured and as a basis for standardized time zones. It passes through Greenwich, England, the site of the Royal Greenwich Observatory, which was founded in 1675 and which closed except as a museum in 1998. The prime meridian, together with its opposite meridian having a longitude of 180°, divide the Earth roughly into the Eastern and Western Hemispheres, with those portions of the British Isles, Europe, and Africa that lie west of the prime meridian, considered for practical purposes as belonging to the Eastern Hemisphere.